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School of Engineering

Mechanics for Modelling

The research area Mechanics for Modelling focuses on analytical, numerical and experimental methods for the mechanical modelling of materials, systems and processes. The focus is on mechanical aspects of the industrial digitalisation. The synergy between realistic experiments, non-linear simulations and data-based methods is systematically used to describe, analyse and optimise complex mechanical behaviour.

The expertise of the research group currently includes mechanical characterization and modeling of metals and polymers, nonlinear structural analysis using FEM and thermo-mechanical process simulation for additive manufacturing, and experimental dynamics for characterization and analysis of dynamic systems. By 2025, competencies in the area of data-based methods (design of experiment, response surface modeling, neural networks, etc.) will be developed.

Material modelling for FEM

The Tear and Fatigue Analyser (TFA) during a crack propagation measurement in which pre-notched Pure Shear test specimens are cyclically loaded. The propagation speed of the crack is measured optically by periodically recording and measuring the contour of the specimen with a camera. Up to ten samples can be tested in parallel with the TFA. In addition, creep tests and fatigue measurements can also be carried out on the system.

The detailed analysis and reliable design of thermo-mechanically highly loaded structures requires a physically well-founded description of the underlying material behaviour. Material models are primarily used in analysis and design by means of nonlinear finite element methods (FEM). Examples range from steam turbines, sealing and damping elements to additively manufactured, metallic components. Particularly in the context of the energy transition, consistent lightweight construction and the realisation of a circular economy, the characterisation and description of the mechanical behaviour of new materials is of special importance.

Our expertise includes the mechanical, thermo-mechanical and thermo-physical characterisation and modelling of polymers and metals. The material models used describe linear and non-linear elasticity, viscoelasticity, plasticity and viscoplasticity as well as fatigue (LCF, HCF) and creep damage for lifetime prediction. Temperature and rate dependencies are also taken into account. Thermo-physical parameters include density, thermal conduction as well as thermal expansion.

Project example: Measurement, Calibration & Modeling of High Performance Polymers

Process simulation for additive manufacturing

Additive manufacturing of metallic components enables the production of complex and highly integrated lightweight and functional parts. At the same time, it has great potential to disrupt the existing manufacturing landscape with its high degree of flexibility and sustainability. However, the great complexity of this promising manufacturing technology requires a great deal of know-how in order to realise the necessary reliability and economic efficiency.

Thermo-mechanical process simulation supports the design and manufacturing preparation of additively manufactured components to improve the reliability and economic efficiency of this promising process. Our expertise lies in the simulation of process-induced thermo-mechanical distortion or residual stresses. For this purpose, both simplified inherent strain and advanced thermo-mechanical approaches are applied. To ensure reliable predictions, we perform a comprehensive thermo-physical characterization of additively processed materials. We further specialize in component-like calibration of all leading process simulation solutions. On our Aconity3D MIDI facility, which we operate in collaboration with the ZHAW IMPE, we develop dedicated in-situ experiments for advanced calibration of laser absorption or thermal conductivity of powders. In this way, we ensure reliable predictions of temperatures, stresses and distortions. On this basis, build-up strategies, support structures and additively manufactured components can be optimized and distortion compensated for prior to manufacturing.

Experimental dynamics

Another focus is on the development and research of novel measurement methods for the experimental characterization of dynamic systems and their application to solve challenging problems in practice.
We apply our expertise in the area of vibration of  and wave propagation in mechanical structures to develop digital models (digital twins), focusing on a comprehensive approach with strong synergies between theory, experiment and simulation. With our competences we cover experimental mechanics holistically. This includes the conceptual design of the measuring equipment, selection of sensors, data acquisition, planning of experimental camapaigns and especially the analysis and processing of large data sets using numerical and statistical methods.

Applications range from classical machine dynamics (multi-body dynamics and modal analysis), to the development and optimization of dynamic systems, to research on sensor technology and measurement methods based on dynamic principles. In addition, we have competences in the analysis of vibrations of rotating systems (rotor dynamics) and their coupling with fluids, as they occur for example in water turbines or as they are used in fluid sensors.

Experimental Infrastructure & Processes

Projects

We conduct research in the field of mechanics and have already successfully completed numerous projects. You can find a selection of these projects here

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